The present invention relates to a process for preparing a .beta.-carotene fortified beverage in order to prevent the loss of .beta.-carotene, more particularly by the admixture of vitamins C, B.sub.2 and E with .beta.-carotene to stabilize the latter even in ambient conditions to minimize its loss in the form of a beverage; in addition, the admixture of such anti-oxidative vitamins is designed in a well-balanced fashion for human nutrition.
.beta.-carotene, now regarded as one of the primary functional components, has been considered to be provitamin A. However, recently its anti-oxidative property has drawn keen attention. Namely, .beta.-carotene has been found to neutralize singlet oxygen which otherwise primes preoxidation of unsaturated fatty compounds. The reactive oxygen is generated from inspired oxygen and results in pathological aging with excess oxidative stress. The effective modulation of reactive oxygen may mean anti-aging. Therefore, there would be no surprise even though the constant intake of .beta.-carotene has been shown to decrease the incidence of cancer, especially lung cancer, in epidemiological research. A lower content of serum .beta.-carotene in a smoker might be due to ample free-radicals in the puffed fume. Therefore, intake of enough B-carotene constitutes a good preventive measure for the most serious kinds of cancer. Thus, it has long been sought to provide any easily accessible source of .beta.-carotene in daily life.
A known beverage containing .beta.-carotene includes carrot juice, as well as the mixture of carrot juice with other juice or juices, with or without fortification of its principal components, and is sold in can, bottle, carton, or plastic container. Even short surveys of this kind of product disclose very poor shelf-life, namely degrading color, flavor and taste over time. Especially, .beta.-carotene is prone to discolor or oxidize by the irradiation of light (C.A. Pesek and J. J. Warthesen, J. Food Science 52 (3), 1987). Naturally, .beta.-carotene is not only photo-sensitive but also reactive with oxygen, reflected by its structure, which makes construction of a long-life beverage containing .beta.-carotene a matter of difficulty.
It is no wonder that so far no effective protection method has been invented for preparing such a .beta.-carotene beverage. We extensively pursued the above aim, namely, how to stabilize the .beta.-carotene moiety in a long-life beverage under ambient conditions without vitiating its flavor and have thus completed the present invention.